As you might have noticed, we have not described what constitutes high, low, or normal levels of most of these hormones and antibodies. So, you may wonder, how do I know if my measurements are normal or abnormal?

Exactly what constitutes normal varies considerably, depending on the lab your doctor uses. Different labs use different standards of measurement. And unlike some medical tests, which quickly reveal whether you do or don't have an infection — a strep culture is an example — thyroid hormone test results must be placed in proper context. This is known as the reference range, which some doctors may call the “normal” range.

A reference range is determined first by testing a large group of healthy people. Levels for this group are then taken together to create a range of what is considered healthy. The result of your test is then measured against a group that is similar to you in age, gender, and health status. For instance, pregnant women would have a different reference range than women of the same age who are not pregnant.

To find out if your hormone levels are normal, ask to see a copy of your lab report. On it, you should see a reference range for each particular test, along with your results.

Essential

To check for hypo- or hyperthyroidism, Dr. Friedman places his hands just a touch below the patient's. If the patient's hands emit coldness, it's a sign of hypothyroidism. If they give off warmth, it's a sign of hyperthyroidism.

Keep in mind that just because your test results fall into the reference range of what's considered healthy or “normal” doesn't mean that you do not have hypothyroidism.

No group test can ever account for all individual differences in these lab tests, and different people will feel differently even if their test results are the same. That's why it's always important to discuss your test results with your doctor and to work toward uncovering the cause of your symptoms. If necessary, request a retest or ask that other tests be administered.